Magnetic entropy change in Ni[sub 50.1]Mn[sub 20.7]Ga[sub 29.6] single crystal.
- Resource Type
- Article
- Authors
- Hu, Feng-xia; Sun, Ji-rong; Wu, Guang-heng; Shen, Bao-gen
- Source
- Journal of Applied Physics. 11/15/2001, Vol. 90 Issue 10, p5216. 4p. 3 Graphs.
- Subject
- *ENTROPY
*ALLOYS
*MAGNETIC properties
*SUPERCONDUCTING quantum interference devices
- Language
- ISSN
- 0021-8979
Magnetic entropy change (ΔS) of a single crystal Ni[sub 50.1]Mn[sub 20.7]Ga[sub 29.6] alloy under different applied fields has been investigated near the martensitic–austenitic structural transition temperature of 219 K. With increasing applied field from 0.2 to 5 T, the sign of ΔS changes from positive to negative. At 0.8 T the positive ΔS reaches a maximum value of about 6.0 J/kg K, and above 0.8 T the increase of applied field results in a negative ΔS. At 5 T ΔS reaches -6.0 J/kg K. The interesting behavior of ΔS is attributed to the first-order martensitic–austenitic structural transition at 219 K on heating. The phenomenon of the considerable magnetic entropy change under the relatively low applied field of 0.8 T and the easy adjustment of the martensitic–austenitic transition temperature indicate that Ni–Mn–Ga single crystal materials may have a possibility for practical applications as magnetic refrigerants. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]